This invention relates to a chip-type circuit element mounting apparatus adapted to handle a chip-type circuit element storing package of a disc-like shape provided therein with a spirally continuous path for receiving chip-type circuit elements therein, and more particularly to a chip-type circuit element mounting apparatus for mounting a chip-type circuit element on a printed circuit board while picking up, by means of a camera, an image of a chip-type circuit element held on a chip mounting head through a chip suction nozzle.
In a conventional chip-type circuit element mounting apparatus (hereinafter referred to as xe2x80x9cchip mounting apparatusxe2x80x9d) which is adapted to mount a chip-type circuit element (hereinafter referred to as xe2x80x9cchipxe2x80x9d) on a printed circuit board, a chip observing camera is fixedly arranged on the side of a body of the chip mounting apparatus. Such arrangement requires moving a chip mounting head to a position of the chip observing camera and then temporarily stopping it at the position or passing it through the position at a predetermined speed in order to pick up an image of a chip held on the chip mounting head through a chip suction nozzle attached to the chip mounting head.
Unfortunately, temporary stoppage of the chip mounting head at the position of the chip observing camera or passage of the former through the latter at a predetermined speed leads to a problem of reducing a speed at which the chip is mounted on the printed circuit board.
Also, a lighting unit required for observing an image of a chip mounted on the chip mounting head through the chip suction nozzle by image processing is divided into two types. One of them is so constructed that a reflection plate is arranged behind the chip suction nozzle to reflect light emitted by the lighting unit, wherein the light is horizontally or upwardly directed to the reflection plate. The other type includes an illuminant arranged behind the suction nozzle.
The prior art permits an outer diameter of the chip suction nozzle of the chip mounting apparatus to be set to be smaller than an outer configuration of a chip, to thereby prevent the chip suction nozzle from interfering with picking-up of an image of a chip through a camera.
However, recent microminiaturization of a chip causes manufacturing of a chip suction nozzle having an outer diameter smaller than a size of the chip to be highly difficult. When an outside dimension of a distal end surface of the suction nozzle exceeds that of a chip held on the chip suction nozzle, an inner side of a contour of the distal end surface of the chip suction nozzle forms a shadow as well, resulting in proper observation of an image of the chip held on the chip suction nozzle being highly difficult.
The assignee proposed a chip mounting apparatus in which a chip storage package of a disc-like configuration is held in a feeder section. The chip storage package is formed therein with a spirally continuous packing path in which a number of chips are stored in a row. The chip storage package provides good replaceability, therefore, use of the chip storage package in the feeder section permits a chip-free or empty chip storage package to be readily replaced with a new chip storage package filled with chips, to thereby ensure continuous feeding of chips from the feeder section to the chip mounting head. This leads to continuous running of the chip mounting apparatus over a long period of time without causing shortage of chips.
When the chip storage package received in the feeder section of the chip mounting apparatus is emptied of chips, it is required to execute an operation of removing the empty chip storage package from the feeder section to return it to an empty chip storage package collecting space of a stocker section and an operation of removing a new chip storage package filled with chips from the stocker section to feed it to the feeder section in order. Thus, a disadvantage of requiring much time for replacement of the chip storage package is encountered with the conventional chip mounting apparatus.
Further, in the case that various kinds of chip storage packages are arranged in the feeder section of the chip mounting apparatus, it is required to identify, on a side of a chip storage package replacement means, a type of chips stored in each of the chip storage packages when it is carried out to remove an empty chip storage package from the feeder section and feed a new chip storage package filled with chips from the stocker section to the feeder section. Thus, it is highly desirable to develop a means of readily and positively identifying a type of chips stored in each of chip storage packages.
In addition, the conventional chip mounting apparatus is generally constructed in such a manner that a height of a chip is detected to control downward movement of the chip mounting head for mounting of the chip on a printed circuit board depending on the height, to thereby render a pressure applied to chips different in height constant. However, such controlling of downward movement of the chip mounting head is deteriorated due to a variation in height of the printed circuit board due to warpage or twist of the board or the like, leading to unexpected damage to chips.
The present invention has been made in view of the foregoing disadvantages of the prior art.
Accordingly, it is an object of the present invention to provide a chip mounting apparatus which is provided with a chip observing camera on the side of a chip mounting head.
It is another object of the present invention to provide a chip mounting apparatus which is capable of permitting an image of a chip to be picked up during movement of a chip mounting head, to thereby increase a chip mounting speed.
It is a further object of the present invention to provide a chip mounting apparatus which is capable of automatically carrying out replacement of a chip storage package to accomplish running of the apparatus over an increased period of time.
It is still another object of the present invention to provide a chip mounting apparatus which is capable of permitting a chip suction nozzle of a chip mounting head to act as a lighting means as well, to thereby appropriately light even a microminiature chip.
It is yet another object of the present invention to provide a chip mounting apparatus which is capable of rapidly and positively carrying out replacement of a chip storage package between a feeder section of the chip mounting apparatus and its stocker section.
It is even another object of the present invention to provide a chip mounting apparatus which is capable of indicating a type of chips stored in a chip storage package by means of a bar code provided on an outer surface of the chip storage package so as to be read by a bar code reader arranged on the side of a package replacement mechanism, to thereby smoothly and positively carry out replacement of chip storage packages even when various kinds of chip storage packages are held in feeder and stocker sections.
It is a still further object of the present invention to provide a chip mounting apparatus which is capable of permitting a height or vertical position of a printed circuit board to be detected for every chip at a location where the chip is to be mounted on the printed circuit board, to thereby minimize damage to the chip during the chip mounting operation.
It is a yet further object of the present invention to provide a chip mounting head unit having a camera integrally mounted thereon for a chip mounting apparatus.
It is an even further object of the present invention to provide a lighting unit for a chip mounting apparatus which is capable of effectively and satisfactorily lighting even a microminiature chip when it is mounted on a chip mounting head through a chip suction nozzle thereof.
It is an additional object of the present invention to provide a package replacement unit for a chip mounting apparatus which is capable of rapidly and positively carrying out replacement of a chip storage package between a feeder section of the apparatus and its stocker section.
It is another object of the present invention to provide a package replacement unit for a chip mounting apparatus which is capable of indicating a type of chips stored in a chip storage package by means of a bar code provided on an outer surface of the chip storage package so as to be read by a bar code reader arranged on the side of a package replacement mechanism, to thereby smoothly and positively carry out replacement of chip storage packages even when various kinds of chip storage packages are held in feeder and stocker sections of the apparatus.
It is a further object of the present invention to provide a chip mounting head for a chip mounting apparatus which is capable of permitting a height or vertical position of a printed circuit board to be detected for every chip at a location where the chip is to be mounted on the printed circuit board, to thereby minimize damage to the chip during the chip mounting operation.
In accordance with the present invention, a chip mounting apparatus is provided. The chip mounting apparatus includes a chip mounting head including a chip suction nozzle for holding a chip thereon by suction, a chip observing camera mounted on the side of the chip mounting head, a lighting means mounted on the side of the chip mounting head to light a background of the chip held on the chip suction nozzle, a reflection means mounted on the side of the chip mounting head to input an image of the chip held on the chip suction nozzle to the chip observing camera, and a feeder section for replaceably holding a chip storage package which has chips stored therein. The chip mounting apparatus also includes a stocker section for replaceably stocking a chip storage package for supply and a package replacement mechanism for carrying out replacement of each of the chip storage packages between the feeder section and the stocker section.
In a preferred embodiment of the present invention, a board mark observing camera is mounted on the side of the chip mounting head.
In a preferred embodiment of the present invention, the storage replacement mechanism includes a plurality of hand sections each constructed so as to hold a chip storage package thereon.
In a preferred embodiment of the present invention, the reflection means includes a first plane mirror obliquely arranged at a position below the chip suction nozzle and a second plane mirror obliquely arranged at a position below the chip observing camera. The first and second plane mirrors of the reflection means reflect an image of a lower surface of the chip held on the chip suction nozzle to input the image to the chip observing camera. Alternatively, only the second plane mirror of the reflection means may reflect an image of a side surface of the chip held on the chip suction nozzle to input the image to the chip observing camera. The first plane mirror may be arranged so as to be retractable to a position apart from the position below the chip suction nozzle.
In a preferred embodiment of the present invention, the lighting means comprises a translucent nozzle cap fitted on a nozzle body of the chip suction nozzle and having a distal end surface for holding a chip thereon by suction, an annular bracket made of an opaque material and formed on an inner peripheral surface thereof with a slit and a plurality of light emitting diodes mounted on the bracket to laterally light the nozzle cap through the slit. The annular bracket is arranged so as to surround the nozzle cap.
In a preferred embodiment of the present invention, the package replacement mechanism includes a plurality of hand sections each provided with an engagement means in a manner to be openable. In the embodiment, the package replacement mechanism may further include an X-Z direction drive mechanism arranged so as to be movable in longitudinal and vertical directions of the feeder section and stocker section and Y-direction drive mechanisms provided independent from each other for the hand sections and arranged so as to be movable in a Y direction, wherein the hand sections are mounted on the X-Z direction drive mechanism through the Y-direction drive mechanisms, to thereby be movable independent from each other in the Y direction.
In a preferred embodiment of the present invention, the chip mounting apparatus further comprises a bar code reader arranged on the package replacement mechanism. The chip storage package is provided thereon with a bar code for indicating a type of chips stored therein, which is read by the bar code reader to identify a chip storage package to be replaced. The bar code may be provided on an end surface of a side of the chip storage package on which an engagement means for replacement is arranged.
In a preferred embodiment of the present invention, the printed circuit board is provided on a surface thereof with a positioning mark through which the chip is to be mounted on the printed circuit board. The camera picks up an image of the positioning mark, to thereby measure a distance between the camera and the surface of the printed circuit board. The chip to be mounted on the printed circuit board may be a surface-mounting type.